change line

CONSTRAINT primary key (CarNo, JobDate, WorkerID))

to

primary key (CarNo, JobDate, WorkerID))

Was the ELSE ***** a sql statement, or several statements?

Nice touch Michael - a good generalization of the solution (though it does need an extra NOT in there to get the right result set)

select * from @t where...

SELECT CharField

FROM YourTable

WHERE PATINDEX('[0-9][0-9]',CharField) > 0

This uses a wildcard range of [0-9] for both the first and second characters of the CHAR field - and if both characters are "hits"...

Yep - but simple can be tricky

A couple of minor items....

This should also be joined on orderid to meet the requirements (although the...

A slightly different approach that avoids grouping, and only has two instances of the same table.

Whether that makes any difference in performance is another question

While this doesn't address your question about what architecture change in 2005 causes your delete to slow down, the following should be a lot more efficient.  Indexing one or more...

before you strip out all characters, note that an autodialer dialing "(800) 555-1212 ext 12"" should dial 18005551212, pause for several seconds, then dial 12.  Your autodialer probably has a...